US PATENT SUBCLASS 246 / 77
.~.~.~ Counting in and out


Current as of: June, 1999
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246 /   HD   RAILWAY SWITCHES AND SIGNALS

20  DF  BLOCK-SIGNAL SYSTEMS {4}
27  DF  .~ Automatic {5}
28 R  DF  .~.~ Electric {18}
77.~.~.~ Counting in and out {1}
78  DF  .~.~.~.~> Ratchet wheel {1}


DEFINITION

Classification: 246/77

(under subclass 28) Counting and cancelling mechanism, usually of the step-by-step variety, is provided, whereby as many trains or car-wheels as enter must leave the block before the signal can be restored to safety.

SEE OR SEARCH THIS CLASS, SUBCLASS:

19, 72, 81, and 247, for systems using propulsion-current, but lacking counting and canceling devices.

19, 78+ and 247, for counting mechanism.

246+, and subclasses mentioned in the search notes appended thereto, for various types of circuit-controllers.